Its county seat is San Antonio, the second-most populous city in Texas and the seventh-largest city in the United States. Bexar County is included in the San Antonio-New Braunfels, TX metropolitan statistical area. Bexar county includes Government Canyon state natural area in northwestern part of the county.
If the screen width is 7 feet and the projector's throw ratio is 2.0 - 2.4:1 (because projectors have zoom lenses, they also have a range of throw ratios) then you can place your projector anywhere from 14 to 16.8 feet away from the screen.
But the more distant an object is, the smaller its parallax. Even with 21st-century techniques in astrometry, the limits of accurate measurement make distances farther away than about 100 parsecs (roughly 326 light years) too approximate to be useful when obtained by this technique.